Flexible humidity and temperature sensor based on cellulose–polypyrrole nanocomposite

Recently, cellulose has been re-discovered as a smart material that can be used as sensor and actuator materials, which is termed as electro-active paper. In this work we demonstrate the application of cellulose as a flexible humidity and temperature sensor. Nanoscaled polypyrrole (PPy) as a humidity and temperature sensitive layer was introduced onto cellulose surface via in situ polymerization technique without disrupting cellulose structure. Atomic force microscopy, UV–visible spectroscopy, transmission electron microscopy and secondary ion mass spectroscopic analysis revealed the successful deposition of polypyrrole nanolayer onto cellulose surface, which is referred as a cellulose–PPy nanocomposite. Effect of polymerization time on sensing behavior of cellulose–PPy nanocomposite was investigated, experimental results revealed that cellulose–PPy nanocomposite with 16 h polymerization time suitable for suitable for humidity and temperature sensor.